Sister Singing ‘You Are My Sunshine’ With Baby Brother With Down Syndrome Is Beautiful [Watch]

Music is therapeutic, and no one knows this more than Amanda Bowman Gray, mother of five. Earlier this year, the Heber City, Utah, resident posted a video of her 11-year-old daughter, Lydia, playing a song on her guitar and singing to her toddler, Bo, who has Down syndrome. While Bo has a vocabulary of about 12 words now, he could sing along to certain words of "You Are My Sunshine" with his sister.

The heartwarming clip has Lydia pausing on specific words as her young brother sings along. At one point, he is seen dancing to the song as he attempts to grab her guitar. The video has amassed over 2 million views on YouTube.

"My daughter Lydia was watching Bo while I was in the shower," Gray captions the three-minute clip. "Came out to this. If she didn’t have a guitar I don’t know if she would know how to babysit him. This is her go to. It’s proof that music therapy works. Bo is 25 months old and has a 12 word vocabulary. Every word he has learned has been through music and singing."

In an interview with ABC News, Gray says doctors told her not to expect her son to talk until he was 3 years old. Music has helped him defy those odds. In addition to Down syndrome, Bo was born with several heart and lung conditions and has spent a lot of time in hospitals undergoing treatment. When the family was given permission to bring a guitar into his room to sing to him, Lydia noticed he could say the word "happy."

"After weeks and weeks (which ended up in months) of being in the hospital in a silent room of the CICU (Cardiac Intensive Care Unit) we got special permission to bring a guitar in and sing to him in hopes that it would comfort him," the mother shared.

"We feel like he's defying the odds," Gray later told ABC News. "Thanks to Lydia and her determination, she pushed forward with music therapy. ... We're so proud of our kids."